red) heart or a
warm coat of fur or feathers; nor was there a single animal that gave
any further care to the eggs it discharged, and left to the natural
warmth of the earth to develop. The extermination of species in the egg
alone must have been enormous.

It is impossible to convey any just impression of the carnage which this
Permian revolution wrought among the population of the earth. We can but
estimate how many species of animals and plants were exterminated, and
the reader must dimly imagine the myriads of living things that are
comprised in each species. An earlier American geologist, Professor Le
Conte, said that not a single Carboniferous species crossed the line
of the Permian revolution. This has proved to be an exaggeration, but
Professor Chamberlin seems to fall into an exaggeration on the other
side when he says that 300 out of 10,000 species survived. There are
only about 300 species of animals and plants known in the whole of the
Permian rocks (Geikie), and most of these are new. For instance, of the
enormous plant-population of the Coal-forests, comprising many thousands
of species, only fifty species survived unchanged in the Permian. We
may say that, as far as our knowledge goes, of every thirty species
of animals and plants in the Carboniferous period, twenty-eight were
blotted out of the calendar of life for ever; one survived by undergoing
such modifications that it became a new species, and one was found
fit to endure the new conditions for a time. We must leave it to the
imagination to appreciate the total devastation of individuals entailed
in this appalling application of what we call natural selection.

But what higher types of life issued from the womb of nature after so
long and painful a travail? The annihilation of the unfit is the seamy
side, though the most real side, of natural selection. We ignore it, or
extenuate it, and turn rather to consider the advances in organisation
by which the survivors were enabled to outlive the great chill and
impoverishment.

Unfortunately, if the Permian period is an age of death, it is not an
age of burials. The fossil population of its cemeteries is very scanty.
Not only is the living population enormously reduced, but the areas that
were accustomed to entomb and preserve organisms--the lake and shore
deposits--are also greatly reduced. The frames of animals and plants now
rot on the dry ground on which they live. Even in the seas, where life
must